add optim_converter script and structure_read.90 to convert OPTIM files
to sqlite database.
reduced time required to plot DG by only building nx graph from
transtion states and minima below Emax. added tree selection feature
Cleaned up scripts
Intermin Gui work
Included nascent colouring features, and completed interactive basin
selection.
colours can be assigned to basins by selecting them
Merge remote-tracking branch 'lsmeeton/master'
Merge pull request #59 from lsmeeton/DG_changes

Dg changes