Fixes the problem where if there isn't anything to replace with, it replaces with "undefined"

https://github.com/yeoman/grunt-usemin/issues/128
Update README.md to include example build task

Resolves #251. Hoping this helps others understand that usemin won't run the concat/cssmin/uglify tasks for you.
changed spelling to below
Merge pull request #338 from chelseakomlo/master

Changed spelling of bellow to below
Modifying CSS RegEx to fix SVG fragment identifiers in font URIs

Fixes “url("/styles/fonts/icons.svg#icons") format("svg”);”

More info: http://www.w3.org/TR/SVG11/fonts.html#FontFaceURIElement
Merge pull request #340 from lukebussey/css-font-fix

Modifying CSS RegEx to fix SVG fragment identifiers in font URIs
Bump to 2.1.1
Explicitly set the files to install.
Minor package.json cleanup.
Update all dependencies to their latest versions.
Clean up JSHint's options.
fileprocessor.js: re-indent.
Remove unneeded jshint inline suppressions.
test/helpers.js: fix check for array.
Minor README.md tweaks.
Merge pull request #347 from XhmikosR/array

test/helpers.js: fix check for array.
Merge pull request #345 from XhmikosR/package.json

Update package.json
Merge pull request #348 from XhmikosR/readme

Minor README.md tweaks.
Merge pull request #346 from XhmikosR/fileprocessor

Update fileprocessor.js
Fixes getCandidatesFromMapping on windows