Fixes #510. If a keyboard.json has no timezone in the last modified date string, then it will still install

History.md and updated platform test report

[Windows][Android][Web] Platform statement consistency fixes

Reworked several aspects of platform constraints esp. regarding unknown constraints. Rewrote keyboard and spreadsheet to facilitate testing more reliably.

[Android] Consolidate "Info" views

Fixes #960

Previously, the InfoActivity was displaying the app version in one view, and launching the help content in another Activity.

Fixes #968. Platform tests on Android now give correct results for hardware keyboard. Partial fix for #966 (hardware keyboard in Chrome emulator).

[iOS] #735 - Allow keyboard update even if languageID not in API results

Also removed kludgy and now unnecessary fall-back code to create a "language" on the fly from an id.

Merge pull request #964 from keymanapp/windows-strip-script-subtag-on-windows-7-keyboard-install-919

[Windows] Strip script subtag on Windows 7 before installing keyboard as script subtag not supported.

Fixes #919 (again). Strip script subtag on Windows 7 before installing keyboard as script subtag not supported.

[Windows] Untitled keyboards will now show the filename of the keyboard in Keyman UI

[windows] Update history.md

[Windows] Fix issues attempting to install custom languages in Windows 7

[Mac] Added switches to control Keyman4MacIM build destination

Fixes sillsdev/keyman-issues#5641. Crash in Keyman Configuration on Win7 when enumerating keyboard custom languages

Fixes #919. Keyboards with custom BCP 47 language tags will now install on Windows 7 with a fallback language.

[Android] Fix globe button for system keyboard

Fixes #913

In #848, we used [webView.pauseTimers()](https://developer.android.com/reference/android/webkit/WebView#pauseTimers()) to disable JavaScript for transitioning between in-app and system keyboards. Unfortunately, `pauseTimers()` globally affects all the WebViews, breaking the globe button in system keyboards.

(This worked going from the Keyman app to in-app browser because the browser "resumed" its keyboard)

Solution is removing calls to `pauseTimers()`. 

[Mac] #894 update history file

[Windows] Improve crash reporting stability