[BH-379] Librarize application-calculator

Librarize application-calculator

[EGD-6960] Header addition related style cleanups

Header addition related style cleanups.

[BH-374] Librarize application-antenna

Add apps-common, librarize application-antenna

Merge branch 'master' into stable

[BH-371] Replace gsl with mainline submodule and move to third-party

Replacing loose gsl files with gsl mainline project as submodule
and moving it to third-party

Merge branch 'master' into stable

[EGD-6835] Fix UT link errors with inotify

Fix UT linkage error when trying to link with
libiosyscalls with inotify mechanism

Signed-off-by: Lucjan Bryndza <lucjan.bryndza@mudita.com>

[BH-365] Move TPLIB (tinyexpr) to separate directory

Move library, amend CMAKE files

[EGD-5884] Added Lock Screen popup handling

Moved lock screen window to popup. Split DesktopMainWindow into
two parts (popup and regular). Added LockPhoneHandler into
ApplicationManager.

[EGD-3119] Hide InputEvent's member fields

Use the InputEvent's convenience methods to express intent.

[EGD-5849] Make calculator compute previous operations

Modify calculator behavior according to PO input:
* Compute existing equation before entering next operation
* Limit digit input to 7 digits
* Start each number input from empty input

[EGD-6563] Don't allow to edit exponent output in calculator

Clear the calculator input field before typing if it contains exponent
output from previous calculations.

[EGD-6527] Internationalization API unification

Single api to rule i18n
all calls to localistaion in cpp files unified
cut off ass many dependencies in i18n header as possible

[EGD-6561] Limit calculator decimals to 6 digits

Limit to 6 since our `utils::to_string(double)' function also
limits to 6 decimals.

[EGD-6561] Make calculator input testable

I got sick of manually testing calculator like a troglodyte.

[EGD-6560] Do not clear "0" on Enter in calculator

Do not treat input string "0" as erroneous.

[EGD-6498] Do not perform calculations on empty input

We do not produce an error when user calculates empty input.

[EGD-6500] Clear calculator input on # long press

Long pound press should clear input text.

[EGD-6494] Application Manager on action switch fix

Application Manager switch on Action no longer causes to
newly opened application main window switch but it
calls declared action handler.

[EGD-6347] Refactored phone modes handling in applications

PhoneModeObserver doesn't work properly in applications.
Applications have to handle the phone mode changes via AppMgr.
Phone mode and tethering handlers separated.