return int from exponent instead of float; remove ilogb
clear helpdb cache when set locale
windows build fixes
Merge pull request #2547 from wlbksy/patch-1

clear helpdb cache when locale changed
deprecate a couple redundant string functions
Merge pull request #2544 from JuliaLang/mn/exponent

RFC: return int from exponent instead of float; remove ilogb
update doc for changed string funcs
Merge branch 'master' of github.com:JuliaLang/julia
deprecate ilogb
improve some comprehension result types
Merge branch 'master' into anj/linalg2