Make button text configurable; change placeholder

for input[type=file]
Closes GH-12
Merge pull request #15 from matthewwithanm/configurable-button-text

Make button text configurable; change placeholder
updating example default widget for uploads
use populated as it's more semantic, though kind of oddball
aligning +s... because I'm THAT guy
customize text details in readme
clean up last row in table for github
Merge pull request #16 from aebsr/configurable-button-text

Updated README, new "populated" class
Add grunt for bumping
Add gitignore
Release v1.4.0