Merge pull request #22 from mholden8/master

Attempting to fix according to transform node API changes.
Added concatenation functionality to transform buffer nodes.
Modifying update system to use Qt signals and slots.
Attempting to fix rounding errors in metric computation for Mac and Linux.
Use specific signals and slots for different events.
Merge pull request #24 from mholden8/SignalsSlots

Fix widget updating
Adding simple sequence metafile reader (not all combinations of transforms are computed).