Add libsir.so interface
Replace Python SIR reading with C version

I also maybe fixed (or not) 1-based and 0-based indexing issues. I need
to double-check that these results are right.
Display SIR header

Need to convert to popup window, but at least the info is available.
Reverse ordering of status bar info
Add menu item for adjusting display range
Update feature list with today's work
Draw zoomer window contents
Fix bug from removing loadsir.py