added -f --file option
added a runMode=file|directory variable and refactored existing code to fulfill the existing 'directory' case
run_applications.sh -> process.sh
DRY queuing of directories
refactor validation methods
extract error messages into environment config
updated usage and examples
README
DRY checking and quitting if ImageOptim or ImageAlpha are not installed
fix Roger Troutman related typo
DRY running ImageOptim and ImageAlpha on a directory
move processDirectory into methods.sh now it's more manageable
handle -f --file option
Merge branch 'develop' into issue-24

* develop:
  README
  1.4.5
  add error messages to env config
  fixes #26, also check for non app store variant of JPEGmini bundle id

Conflicts:
	bin/imageOptim
	environment/base.json
	src/shell/methods.sh
applied fix for #26
read from stdin rather than have a --file option
break large methods.sh into categorised files
decouple launching an app from waiting for it to finish
process files piped in, fixes #24
don't point at a global for the path when processing a folder