io: Adding io_file_read function

This function reads the given filename automagically.
io: Some improvements to the io_read_file function; verify: remove double printf
main: disable old manual read, tweak printf.
Change the length printf.
Remove some trailing whitespace.
Remove some stuff that we don't need to test anymore.
string: starting on string module.
string: Yay, it [string_gsub] works (big commit)! :D
string: forgot if we don't have an occurence but the first character of tsub matches string[i] case, started adding comments
main: add \n\na to start and end of original to verify that the algorithm works at both start and end of string; string: add comments and do some small tweaks to the algorithm, remove copious output.