Add chunk preprocessing facility.
Document feature better.
Fix parallel uploads.
Merge pull request #55 from srijs/feature-preprocess

Add feature to preprocess chunks prior to testing & sending.
Implement forceChunkSize option
Implement Resumable.addFile
Implement for real.
Merge pull request #57 from srijs/feature-add-file

Add possibility to add file manually.
Merge pull request #56 from srijs/fix-last-chunksize

Fix the last chunk size dilemma.
Implement first version of getOpt.
Clean up implementation.
Move option init.
Missed two lookups.
Merge pull request #59 from srijs/feature-getopt

Merge getOpt implementation.
Previous commit had snuck in a syntax error, fixing
Fire an `uploadStart` event.
Support for `minFileSize` and `maxFileSize` settings.
Solve issue #54 (copied in #58) where the main `query` setting would be poluted by data from each Resumable chunk.
Fixed typo with a 'bytes' too many in error messages.
Updated the introduction to Resumable.