Extend functionality of MeasurementSets
test putData and getData!
Merge pull request #6 from mweastwood/improvements

add functionality to the MeasurementSet type
Delete unused immutable
Revert "Delete unused immutable"

This reverts commit 225413b26c6799c9509046bf01cca6e469a53479.

Turns out that immutable was being used after all. Oops.
Refactor get and putColumn

I've come to realize that getColumn is inherently type unstable.
Therefore I want to expose getColumn!, which forces the user to specify
the type and shape of the column.
Export getColumn!
Remove the general getColumn/putColumn for MeasurementSets

I want to guarantee type stability with the MeasurementSet interface.
More MeasurementSet tests
Merge pull request #7 from mweastwood/improvements

Type stability fixes and more tests
Fix getTime and getFreq
Add mention of MeasurementSet interface to README
Re-write c++ getColumn and putColumn to use templates

This reduces code duplication
Implement putKeyword for strings
Add tests for getFreq (exporting putKeyword!)
Refactor getKeyword and putKeyword! to be more generic

This will make it easier to get and put keywords that are not strings,
which will be implemented as soon as I need it (ie. not yet)
Merge pull request #11 from mweastwood/improvements

Various fixes and improvements
Fix an error in the README
Check to make sure libcasacorewrapper.so is built
Rename table finalizer to close and export close