[DOC] MM - Documented the Kernel HEAP allocator.
[DOC] MM - bt_page - Renamed the headline to PAGE allocator.
[DOC] MM - Added some pre-liminary documentation to the Virtual Memory Manager.
[DOC] MM - slab - Added some initial documentation to the SLAB allocator.
[INTERFACE] FS - Added fsinfo interface to the file-system interface ops.
[FS] Added a BT_OpenFile() api macro, accepts the stdio mode strings directly.
[FS] Added MountPoint querying API.
[FS] FullFAT - Added support for the fs info operation.
[SHELL] df - Added a basic implementation of the df (disk-free) command for interrogating mounted partition information.
[MACH] zynq: support of different uart modes (number of data bits, parity, stop bits) added
[NET] mac configuration changed
[MACH] zynq i2c: fix so that reading of more bytes than the fifo size is possible
[MM, SLAB] function realloc implemented
[DRIVERS] SDHCI - Hard-coded the SDHCI controller clock to be within limits on ZYNQ

This should really be adapted to calculate the divider automatically.
[DRIVERS] SDHCI - Fix compiler warning|error.
[FS] FullFAT - separate semaphores for locking FAT and DIR functions added
[MACH] zynq uart - simple buffered mode (without using a queue) added
Squashed 'os/src/shell/jimtcl/' content from commit eff89bb

git-subtree-dir: os/src/shell/jimtcl
git-subtree-split: eff89bbd45fce0af30d819718076a3d0890f6a5a
Merge commit '1d719ec6505ec9c0336267a0f15b3586aeab0b71' as 'os/src/shell/jimtcl'
[SHELL] JIMTCL - Provided a working configuration for JIMTCL on BitThunder.