Mercurial support
Updated README with limitations and vcs configurations
Fixed arguments of hg commands
Added pre-commit script for mercurial
Added instructions for mercurial pre-commit
Fixed tests for mercurial
Fixed e2e test
Fixed pngcrush linter
Added E2E tests for mercurial
Added tests
Added tests
Replaced fail() with assert*()
Small E2E refactoring: removed unused method and reorganized the code
Small E2E refactoring: added base class
Added teardown for e2e
Merge pull request #30 from sk-/mercurial

Mercurial support and e2e fixes