fix(tools): make smt2 separate module
chore(tools): update Makefile
feat(tools/smt2_stat): add extract_nonlinear_func
benchmark(hybrid_systems/bouncing_ball): fix bouncing_ball.drh to be infix-form
fix(tools/proofcheck/checker/lexer.mll): add support "inf" symbol
fix(tools/smt2_stat): consider Pow(e, 0.5) as "sqrt" function
doc(tools/flyspeck_code): update README
feat(tools/smt2_stat): add print_infix_formula
chore(travis): update secure keys
doc(README.md): use shield.io icon for builds
chore(travis): install cmake and automake for OSX build
chore(travis): install cmake and automake for OSX build