Fix thread_yield by avoiding the (too) early re-enablement of IRQ,
that is: before the newly selected thread's context is totally restored
Prevent the compiler to add an unwanted prologue in thread_yield()
Fix the race condition when an interruption occured at the beginning
of thread_yield(), i.e.: just after SR(R2) was pushed but before
the rest of the suspended thread's context was pushed!
Fixed comments
drivers-lm75a: use sizeof array instead of reg_size
lint: reduce scope

Fix some lint warnings of kind
```
style (variableScope): The scope of the variable '…' can be reduced
```
cpu: lpc_common: reduce indentation level in iap.c
Merge pull request #1565 from Kijewski/scope

lint: reduce scope
Merge pull request #1618 from rousselk/msp430-fix-thread-yield

Fix thread_yield() on MSP430 platforms
example: adapt README to new naming of the transport layer
Merge pull request #1660 from mehlis/udp-tcp-split-readme-fix

example: adapt README to new naming of the transport layer
cpu/examples/sys/drivers: reduce scope of variables
force travis to use 4-* (4-8-2014q2-0precise9 or newer) gcc-arm-none-eabi due to a bug not
installing the c++ headers when installing the stock cross-compiler
boards: msba2-common tools: reduce scope
dist: linux-border_router: reduce scope
Merge pull request #1657 from N8Fear/scope

lint: reduce scope (2)
Merge pull request #1605 from BytesGalore/fix_travis_arm_none_eabi_cpp

travis: force specific compiler branch to install the c++ headers
sys: remove break after return
Merge pull request #1661 from N8Fear/duplicate

lint: remove break after return
board/sys: move bounds check before array access