Boost 1.57
Change default config location
Use new config location
Config SHA1 calculation script
Add module hunter_calculate_config_sha1
Remove guards
Allow config.cmake customization (issue #17)
Forward HUNTER_CONFIG_SHA1 to external projects
Use first 7 SHA1 digits to create directories
Use first 7 SHA1 digits to create directories (config)
Check config-sha1 short collision
Update .travis.yml
Allow list variables for CMAKE_ARGS
Update clang: 3.5.0
Clean-up module: hunter_config
Improve error message
Add GSL
Add GSL example
Add clapack
Add clapack example