Add support for write all

This commits adds support for write all through a global variable called
g:vroom_write_all, if it's equal to 0 (default) it will save only the
current file, if it's equal to 1, it will save all files prior to
running specs.
Clear screen before running tests

This feature is controller by the g:vroom_clear_screen setting, which is
on by default.
Merge remote-tracking branch 'emxyzptlk/write_all_support'

* emxyzptlk/write_all_support:
  Add support for write all

Conflicts:
	autoload/vroom.vim
	doc/vroom.txt

closes skalnik/vim-vroom#1
closes skalnik/vim-vroom#2
Merge pull request #3 from eMxyzptlk/write_all_with_clear_screen_support

Write all with clear screen support
Scope vroom_test_file to the current tab.
Merge pull request #4 from stevenharman/scope_test_file_to_tab

Scope vroom_test_file to the current tab.
Default colors on for terminal Vim, off for GUI
Merge pull request #6 from stevenharman/default_colors_on_in_terminal_vim

Default colors on for terminal Vim, off for GUI
Suppress "map already exists" error
Don't include color flag for Test::Unit

Fixes #7
Update ALL the docs
Update README with link to vimmified docs
Fix broken link in docs
Update to 1.0.1
added support for configurable cucumber path
fix docs
Merge pull request #8 from prognostikos/master

Support for configurable path to cucumber
Bump doc version and start work on changelog
Adds support for detecting spec_helper for bundle exec

Closes #9
Bump version of plugin