Cosmetic (switch ' for ")
Cosmetic
Don't override source if folder exists

* Bump SDK version to 6.1
* Minor improvements on logging
Updated to build curl 7.29.0
Add support to build with debug symbols
Merge remote-tracking branch 'origin/master' into ruby-1.8

Conflicts:
	build_curl
	lib/curl_builder.rb
Merge pull request #16 from akikoskinen/ruby-1.8

Updated the Ruby 1.8 branch to reflect the current master branch