[NUCLEO_F072RB] Remove call to systick
[NUCLEO_F091RC] Remove call to systick
Fix a bug that I2C driver can not transfer of 1Byte/2Byte.

I2C driver was not considered about 1Byte/2Byte transfer.
Add 1Byte/2Byte transfer processing in I2C driver.
Fix a bug that initialize setting of SPI clock value is not correct.

Modify the value as below.
　uint16_t mask = 0x000c0; ->
　uint16_t mask = 0x000c;
Fix some bugs that IRQ Edge Interrupt will not operation normal.

The bugs of IRQ Edge Interrupt as below.
- Not call a function that was registered in rise, always call a function that was registered in the fall.
- If there are multiple interrupt sources, there is a possibility that end the wrong interrupt processing.
Add definition of User button(SW0 and SW1)

Add definition of User button for users.
Ignore cscope and vim swap files
[STM32xxx] CoIDE exporter and gcc_arm

- CoIDE options: wrap main and linker option DiscradUnusedSection=1 was
missing in some targets
- CoIDE options: corrected flash loader config for Nucleo_F030 and
Nucleo_F072
- CoIDE options: corrected memory layout (not used per default but now
it is the same as in linker script)
- gcc linker script: changed the memory size from hex number e.g. 0x2000
to decimal 8K
[STM32xxx] gcc_arm startup files

Updates startup files to actual versions of STM32 Cube drivers without
any changes of STs drivers:
- DISCO_F303VC
- DISCO_F334
- NUCLEO_F030
- NUCLEO_F072
- NUCLEO_F302
- NUCLEO_F334
[DISCO_F4xx] add PeripheralPins.c/.h
[DISCO_F303] missing wrap main in gcc_arm template
Fix a bug that usticker wait interval is not constant.

When read the timer value, it have a potential to read abnormal value.
Because we used 16bit + 16bit cascade timer and read timer count separately.
Changed usticker timer from 16bit + 16bit cascade timer to 32bit timer to fix the bug.
Merge pull request #767 from ohagendorf/nucleo_disco_coide

STM32xxx: CoIDE/gcc_arm exporter and startup_stm32xx update
Merge pull request #766 from ohagendorf/reorg_hal_stm324

Targets: DISCO_F4xx - add PeripheralPins.c/.h
Merge pull request #764 from shirishb/master

Gitignore - Ignore cscope and vim swap files
Change I2C driver transfer sequence

Change I2C driver transfer sequence to go according to H/W manual.
Changed contents are as below.
- Access procedure of ACTBT bit of MR3 register
- Issuance procedure of stop condition
Fixed IAR serial fgets fgetc
Add support for mDot with STM32F411RE processor
[HAL][K20D50M] Serial baudrate improvements / clk_freqs.h fix

Three changes, first it fixes:
https://github.com/mbedmicro/mbed/issues/761 (which was reported
slightly wrong because K20 has again different clocking from KLXX for
uarts).

Second it adds mcgpllfll to clk_freqs, which again is different for K20
compared to KLXX .

Finally it adds the fractional baudrate divider for more accurate serial
baudrates.
Moved IAR serial differences to retarget.cpp