Optimize (x&A)<<B>>B.

Add an optimization to simplifyExpressionsPre to replace (x&A)<<B>>B with X&A
if possible. This comes up frequently in C++ with bool variables.
do not call code-running callbacks if ABORTing; fixes #1191
Browser.safeCallback
handle dynamic indexes properly, even out of bounds, for array gep lookups; fixes #865
add 2011 splash slides
fix argument counting regression from 5efd506 ; fixes #1202
actually implement clock_gettime()
add linpack benchmark
Add myself to the AUTHORS file.
Merge pull request #1204 from sunfishcode/incoming

Optimize (x&A)<<B>>B.
handle ./ in file packaging