Implement missing tests

How embarrasing…
Add error level for informational annotations
Use note level messages where applicable
[Fix #251] Handle abbreviated file names from luac

We simply ignore file names from luac.  If anything breaks, we
conveniently blame luac.

Thanks @ptrv for reporting
Remove -property option from D checker
Support alternative ruby modes
[Fix #214] Merge branch 'feature/auto-refresh-error-list'

* feature/auto-refresh-error-list:
  Switch to error list source with mouse-1
  Show source name in error list mode line
  Don't consider error list as modified
  Simplify error list highlighting code
  Highlight and synchronize errors list dynamically on post-command-hook.
  Fix highlighting of first error in the list
  Simplify re-centering
  Update documentation of the error list
  Automatically update error list when switching buffers
  Refactor error list source management
  Use the real error list source buffer when refreshing
  Simplify restoring of the selected window
  Remove broken test cases
  Automatically recenter the error list at highlighted errors
  Update the changelog
  Refresh the error list when clearing Flycheck state
  Highlight errors at point in the error list
  Remove function to display errors in list
  Improve naming of error display functions
  Automatically refresh error list after syntax check

Conflicts:
        doc/flycheck.texi
        flycheck.el
[Fix #257] Close defface sexp

Regression from 9adc768, thanks to @gja for reporting and fixing.
Remove obsolete checker declaration macro
get rid of Enhanced-Ruby-Mode
Merge pull request #256 from peterhoeg/master

Support alternative ruby modes
Fix headling in changelog
Update the changelog
Remove dead test cases

These test cases are for non-existing code.
Simplify version info retrieval
Merge pull request #260 from tom-tan/d-delete-property

Remove -property option from D checker
Test go with GOPATH set

Go mandates the existence of this variable for Go code, see
http://golang.org/cmd/go/#hdr-GOPATH_environment_variable [golang] moved
Write Go output to temporary file

Writing output of the go compiler to /dev/null is not supported as go
checks for existence of the output and denies overwriting. Added a
helper for creating a temporary filename (without creating the actual
file) and sending output to this file. Flycheck takes care the file is
removed afterwards.
Improve temp file name generation

Rename the symbol to temporary-file-name to adhere to Emacs' naming
conventions, and create the temporary name in a sub directory of the
temporary directory to prevent symlink attacks.

Remove the extra function to generate temporary names.
Document temporary-file-name in the manual