[Fix #511] Explicitly inherit Emacs Lisp load path
Move test support code into a separate library
Rename -testlib to -ert
Fix testsuite indentation
Test indentation of all Emacs Lisp sources
Fix indentation
Rename the test runner

run.el is simply shorter and more to the point
Include ERT extensions in package
Remove redundant dependency

ERT is part of Emacs proper, so we don't need to depend on it.
Update documentation about the test suite layout
Fix reference to option

[ci skip]
Add documentation for the test API
Properly restore old state of global mode
Change the semantics of flycheck-should-errors
Add byte-compilation rule for flycheck-ert
Fix pmake test case
Merge branch 'test-api'

* test-api:
  Fix pmake test case
  Add byte-compilation rule for flycheck-ert
  Change the semantics of flycheck-should-errors
  Properly restore old state of global mode
  Add documentation for the test API
  Update documentation about the test suite layout
  Remove redundant dependency
  Include ERT extensions in package
  Rename the test runner
  Fix indentation
  Test indentation of all Emacs Lisp sources
  Fix testsuite indentation
  Rename -testlib to -ert
  Move test support code into a separate library
Update changelog and texinfo manual
Fix table of contents directive
Fix function name