Fixed integer-only Newlib stubs

Newer Newlib versions use different functions to implement integer-only versions
of printf/scanf. Our stubs were modified to take advantage of these changes and
keep the code size low in integer-only versions of eLua.
LM3S platform specific PIO module

New module on the LM3S platform which deals with platform
specific PIO setup functionality.
fixed compilation issue when INT_TMR_MATCH is not declared
GPIO interrupt support on LM3S + systimer fix on 9B92/9D92
removed debugging printf statements
LM3S: timer interrupt support
LM3S platform fixes

1. fixed "uart_setup" function
2. enabled UART buffering
3. changed invalid keys in lm3s.pio
added explicit GPIO mappings for UART
LM3S platform specific PIO fixes

Changed the LM3S platform specific PIO module to be consistent with
the generic PIO module's API.
stext and etext fix
Merge pull request #12 from molnarkares/master

stext and etex fix (tracker #44)
fix handling of rotables in luarpc
Preliminary directory support

- For now only supported for MMCFS
- 'dir' function in shell augmented to show directories and
  to traverse a path recursively if requested
- new command 'mkdir' in shell
More improvements to the shell (WIP)

- file masks ('*' and '?' are now accepted)
- recursive operations for ls/cp
- new FS-specific functions (src/common_fs.c)
added MMCFS emulation under the simulator
added MMCFS emulation under the simulator
Adding rm and rmdir commands to the shell (WIP)
'mv' command and shell code refactoring

There is a new command in the shell ('mv' - move/rename files).
Also, the shell code was refactored into its own directory (src/shell).
The 'help' command in the shell was updated and supports 'help <command>'.
There is a new BUILD_ADVANCED_SHELL build time macro that enables the
advanced shell features (currently 'cp' with recursion (and other improvements),
'mv' and 'rm').
shell fix for shell_recv
Small memory optimization in Lua strings

Get rid of the "reserved" byte in the TString data type. Might actually
save more than one byte, depdending on the compiler structure alignment
rules (and the architecture). Tested with the Lua 5.1 test suite.