Introducing check for file existence with regexp, fixes #174

check for api

added new api method

added check for new steps

implement new steps

Git complained about missing \n

Added matchers for file and regex

Implemented file matchers

Load matchers

Added checks for existence of file via plain match

Use check_file_presence for regex as well

One method for all

Change the steps for matching regexes
The use of /regex/ is not ideal -> Paths can contain "/". Therefore
I chose %r<regex> as matcher

Accidently deleted test

Add test to check for mixed conditions

Use custom matchers to generate better error messages

New api for file matchers

Implement new api for file matcher

Use new api of file matchers in aruba api

Added the rspec matchers class again

Inline classes

Use should syntax

code cleanup and reduction