Fix for Android Studio 2.3.x freeze when in Layout Preview.

[zawadz88]

This PR solves issue #202 i.e. it fixes Android Studio 2.3.x freeze when in Layout Preview and adds a workaround for invalid previews in Android Studio 3.x.
Update plugin versions and build tools to the newest ones.
Additionally, it updates the library version to 4.3.1

[codecov-io]

Codecov Report

Merging #215 into master will increase coverage by 0.08%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master     #215      +/-   ##
============================================
+ Coverage     85.32%   85.41%   +0.08%     
  Complexity      266      266              
============================================
  Files            30       30              
  Lines           995      994       -1     
  Branches         85       85              
============================================
  Hits            849      849              
+ Misses          118      117       -1     
  Partials         28       28

Impacted Files	Coverage Δ	Complexity Δ
...epstone/stepper/internal/type/TabsStepperType.java	73.07% <0%> (+2.7%)	5 <0> (ø)	⬇️

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