Adding doxygen generated documentation (doc.zip).

1. Additional doxygen configuration with full call/caller graph generation.
2. Generated html doxygen file for users that do not want to generate.
Updating README.
Updating README.
Adding additional reference documentation for devices.
Adding reference to AVR application note.
Cleaning up documentation.
Adding a font class for handling GLCD fonts. Refactoring FixedNums8x16.
Cleaning up documentation.
Cleaning up documentation.
Making a run through the documentation.
Example sketch build size added.
Small update after update of AT24CXX driver.
Making a run through the documentation.
Removing class overview files as this is now available in the documentation.
Removing the makefile as it has limited contents and requires doxygen/dot.

1. Full callgraph is also removed as this has limited interest for users.
2. Update readme; removing all references to the overview and makefile.
Making Periodic an abstract class.
Correcting Pin print function. Missing carriage-return-line-feed.
Increasing IR receiver robustness with watchdog timeout.
Adding a main page to the doxygen generated documentation.
Updating benchmarks to following example sketch naming.