Subframe integrate

Resolves #262

1. Added SubframeIntegration which is where almost all integration is now done. This was motivated by the fact that most functions (expecially peak prediction and refinement) do not require integrated peaks, and the fact that you had the option of integrating on the same frame was confusing. I have left the Pixel sum integrator in SubframeFindPeaks because integrated peaks are required for autoindexing.

2. Decoupled shape collection building and prediction, so that a shape collection is now no longer required to predict peaks. Now, predicted peaks are discarded at the point of integration if their profiles are invalid.

3. Improved the safety of the GUI by disabling buttons for core functionality on all subframes when the data is not available.