* Removed the `php.ini` configuration bits from both MAMP and Homebrew instructions, both actually come with reasonable defaults now (high `memory_limit`, `error_reporting` on full, `date.timezone` set).
* Removed chapter about package install, we should favour composer now
* Compressed the install wizard instructions
Added installation steps for Composer using the global installation of PHP and the MAMP installation of PHP.
Note that the use of HTML instead of standard Markdown was due to Markdown incorrectly handling nested ordered lists. This wasn't my preference, but I felt having consistent and clear styling of sub menus overrode ease of use as plain-text.