GUI autoindexer fix and modification

Resolves #146 (closed)

This merge request:

1. fixes a bug in the GUI autoindexer, caused by Peak3D::setMillerIndices. Since there is no unit cell assigned to an unindexed PeakCollection, this function was setting _selected = false for all peaks, causing them to be filtered out during indexing.
2. adds implicit filtering in SubFrameAutoIndexer. In practice, it's a pain to generate a new PeakCollection via the filter peaks tab every time you want to change some parameters in the indexer tab. Therefore, I added spin boxes to select the frame range, D range and strength under the indexer tab.
3. adds a "selected" column to all peak tables, making it more clear which peaks will not be used in a calculation. Also makes it more obvious which peaks will be removed by the state->selected filter.