[MOS-530] Various calculator app fixes

* Fixed issue with subtract operation triggering unusal behavior.
* Unified handling of the add,sub,mul,div operations.
* Updated and verified existing unit tests and added new ones covering
unhandled cases.
* Added basic requirements/readme.

[MOS-893] Fix invalid time description in the SMS thread

The sending/receiving time information will be displayed as follows:
- Only an hour –> for today
- Yesterday and hour –> for messages received/sent yesterday
- Day of the week and hour –> for messages received/sent within
last 7 days
- Date (day+month) and hour –> for messages older than week,
but still from the same year
- Date (day+month+year) and hour –> for messages
rom previous years

[MOS-196] Add days of the week to the list of SMS, calls and notes

If an event (e.g. receiving a call or SMS) happened
in the current week, we display the days of the week
instead of the date on the list.

[MOS-192] Time should not include 0 at the beginning

Fix for displaying an additional 0 at the begging of the clock.
It affects the clock in the status bar and messages and calls time.

[MOS-807] Unpacking update package

* Added unpacking and validating of
update package
* Removed 'utils-bootconfig'
* Added 'tar' module
* Minor compilation issues fixed

[MOS-783] Change boot.bin to os.bin

Change the confusing system binary name.

[MOS-783] Fixed tests and simulator for Harmony

Fixed tests and simulator for Harmony
after implementation of new filesystem
structure.

[MOS-783] Moved battery config file to '/user/data'

Moved battery config file from root
directory of user partition to
'data' directory to comply with
new directory layout design.

[MOS-783] Fixed Pure unit tests

Fixed (most of the) hardcoded
paths in Pure's unit tests.

[MOS-783] Working Pure simulator after partition changes

Fixed iosyscalls so that Pure simulator
works after directory structure changes.

[MOS-783] First part of new dir structure implementation

    Works:
    - generating .img for Pure;
    - Pure boots after flashing new image and
    seems to be working fine;

    Not yet:
    - generating update package;
    - generating image for Harmony;
    - simulator;
    - path-related unit tests fail
    due to paths being hardcoded
    in test scenarios.

[MOS-275] Fix alarm rings on the low battery screen

When we had a critical battery level and the alarm clock rang,
it was impossible to turn it off.

[CP-1512] Add crashdumps indexing

Adding indexing to crashdumps to to ensure resistance to the device date
retraction.
When max crashdump count reach the file with higher index number will be
remove.

[MOS-737] Fix for adding a country code prefix to existing contact

Adding or removing country code from existing contacts number is
changing now number record itself, exactly when changed number
is placed in DB, instead to create new number record, to avoid
miss match during matching numbers.

[MOS-641] Fix SIM cards window

Creating menus and actions depending on the SIM card
lock status.

[MOS-775] Create run-time statistics for tasks

Every hour, statistics of tasks that put a heavy load
on the CPU will be logged

[MOS-779] Fix music files extensions case sensitivity

Fix of the issue that only files with
extension in lowercase were detected
and listed in the music player's
library.
Additionally code cleanup.

[MOS-26] Add tethering info on status bar

When tethering is on, info appears in the status bar
and network coverage indicates "no connection"

[MOS-550] Improve refresh of the display

1. Implement partial refresh.
2. Implement refresh canceling mechanism.
3. Refactor some parts of the gui and display code.

ad 1.
- Detect parts of the screen changed since last update and merge them
  into bigger regions. These regions defines parts of the context sent
  to the display.
- Refresh the region covering all of the parts since this is the most
  time consuming part and the size of the refreshed region doesn't
  change the time much.
- Refresh the whole screen if deep refresh is requested and previously
  fast refresh was used. This is needed to prevent unwanted artifacts
  in some cases.

ad 2.
- Separate display update and refresh logic.
- Divide image display message handling into two handlers, one updating
  and other one refreshing the screen.
- Add cancel refresh message and use it to cancel refresh during update.
- Store sum of refresh regions gathered during updates to refresh them
  all at once at the end.

[MOS-550] Revert - Implement eink partial refresh

This reverts commit 41d6e786b6264925caac34650d512e30b8848f8d.