Update links in Readme.md

Link to FRDM-K64F page, add Nucleo-F302R8, LPC800-MAX, DipCortex-M0, DipCortex-M3, BlueBoard-LPC11U24, link to mbed Platforms page at top of "Supported Microcontrollers and Boards" section.
Merge pull request #335 from thomasrussellmurphy/patch-1

Update links in Readme.md