Configure options reorganization
Make git ignore bench_recover when configured with benchmark enabled
Merge pull request #165

6a59012 Make git ignore bench_recover when configured with benchmark enabled (Pavel Janík)
Merge pull request #160

1ba4a60 Configure options reorganization (Pieter Wuille)
Optimize _double_var

- Save 1 _fe_negate
- Prefer operations on local variables
- Reorder code somewhat to group inline function calls together