Merge pull request #4 from Jeff-Ciesielski/staging

Staging
Added I2S functions init functions.
Merge pull request #5 from ndreys/staging

My changes to libopencm3
Merge branch 'staging' of github.com:iCD/libopencm3 into staging
First draft of additions for audio
Fixed ISOC IN transfers

Needed to add a handler to stm32fx07_ep_write_packet to add support for
ISOCHRONOUS IN transfers. Checks for ISOCHRONOUS type and then handles
the ODD/EVEN frame bits
Restored original optimization setting to makefile
Removed debug code from blocking_handler
Fixed various whitespace problems
Added check to i2s_disable for required conditions

BSY must = 0 and TXE must = 1.
Removed debug line
Added ISOC IN, USB Audio Class, and I2s

Added Isochronous IN transfers and descriptors for the USB audioclass.
Also added initialization functions for I2S to SPI.
Merge branch 'staging' of github.com:aspalmer/libopencm3 into staging
Changed uint8_t to u8
Replaced if with while loop for i2s_disable
Merge pull request #6 from aspalmer/staging

All of Andrey's concerns were addressed
stm32/spi: Fix missing brace (broken commit)
usb: Replace num_altsettings (broken commit)
Merge pull request #8 from Jeff-Ciesielski/staging

Staging
Merge pull request #9 from ndreys/staging

Add GPIO configuration helper function