fix convert path on windows
add miss correction on paths
Added /usr/bin to default paths
Add custom regex settings

Add logic to test user-defined regular expressions and pass to ImageMagic.
Merge pull request #40 from stormslowly/master

fix convert_path getting way on windows
Merge pull request #45 from jbrooksuk/master

Added /usr/bin to default paths
Merge pull request #52 from tdhsmith/custom-regex

Add user-defined regex option