Merge pull request #1 from hatton/master

Update README.md
Update README.md
Add new command-line options

Allow to specify the filename, project, & build on the command-line
so that the file can be created (instead of requiring the file
to be named buildupdate.sh).
Merge branch 'master' of github.com:chrisvire/BuildUpdate
Command-line option arguments are not optional
Update README.md
Add -r (root_dir) option && only mkdir dir once

Allow the script to be run from the build directory (don't assume
it is in the root directory of the project).  Also, only try to
create the output directory once instead of for every request (it
wasn't broken, just smelled a bit).
Remember the root_dir used when creating the file
Change the path separators to be unix style
Oops.  Can't modify the key
Fix : 400 Bad Request errors for projects with no version control system defined (e.g. simple artifact delivery projects).