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.
- Added manifest logic docs
- More obvious pointers to flushing
- Removed Director page since it duplicated a lot of information already presenting in routing,
which in itself is already duplicated between routing.md and controllers.md.
- Merged Director execution rundown into main exec pipeline docs
- Moved YAML security note from main installation docs to "secure coding", making it sless obvious
