Find studies by modalities in study (0008,0061)
rspec setup with mocha framework
Add examples for DClient#find_studies along with necessary refactorings
Add handling for required, optional and unknown query parameters in DClient#find_studies
Refactor DClient#find_studies (renaming)
Refactor spec for DClient#find_studies (renaming)
Increment version info to 0.8.2c
Fix bug: reset previous query parameters for DClient#find_studies
Increment version info to 0.8.2d
A minor update to the rakefile.
Added a more complete list of optional attributes for the find_studies() method. Reassigned Study Instance UID as a required attribute.
Increment version to 0.8.2e
Some refinements to error messages raised when parsing DICOM files, and changed behaviour to immediately abort when encountering an invalid data element with odd value length.
Rewrote the find_series() method to accept a couple of optional series level query parameters.
Increment version to 0.8.2f
Rewrote the find_images() and find_patients() methods to accept some optional image/patient level query parameters.
Increment version to 0.8.2g
Updated github web address.
Added the dicom extensions.

Added specs for all extensions.
Fixed rspec-setup.
Using bundler for dependency-management.
Now depends on active_support (this could be removed and replaced
with a few simple methods perhaps).
Added comment on binary encoding.