add tests for some helper functions
fix https so it doesn't think http and https are the same length
add contract tests
add www. tests and trailing newline
fix http? to https?, remove www from grab-http because it's unsupported
actually remove www in grab-http this time
add contracts and refactor
add tests for 'hex'?, notes about refactoring 'hex?'
replace 'hex?' with 'hex-string?', add tests for it, and update remaining code to use it
changed a (define (arg) ...) to a (define (lambda (arg) ...))
add more hex-string? tests
Merge branch 'Halfwake-master'