Rename config file

'config.php' will be required by the code, but the repository will not
contain any 'config.php', just this sample file users will have to
copy and edit.
Ignore config.php
Provide an already created cache directory

Default configuration sets caching to true, so let's provide a working
environment with less user initial setup tasks.
Rename SQL script and revamp it

- use InnoDB tables
- ensure utf8
- add db name
- change table name
- change fields names
Set default options consistent with DB script
Fix multiple primary keys bug
Trivial, clean empty spaces
Update to use mysqli
Remove unneded file
Do not create cache directory from script

It's already provided by repository.
Update to new column names
Fix forgotten variable sign
Use require_once()
Move functions into a library file

Let's don't mix script logic and function definitions.
Replace control logic on shortener script

Instead of checking the positive case, we check the ones that would
make our script fail and we avoid an indent level.
Replace remaining braces with new style

I like if/endif, for/endfor, etc. Let's don't mix styles.
Define time zone
Move ini settings to configuration

And provide means to differentiate development from production.
Correct author contact link
Update author comments