Added peek() function to ringbuffer
Set timer mach interrupt to disabled by default
Implementing new way to set hook functions from interrupt routines.

This may allow running of tasks from lower priority interrupts or
thread mode hanlders.
Set interrupt priorities so that UART may preempt SysTick.

This allows lower priority handlers to be run from Systick interrupt.
Modifications to interrupt handling.

Added low priority event loop handling in TIM14 interrupt.
Removed all timer prescalers, seems to work now.
Modified systick to use counter and modified wait_ms() to use this counter.
Set Systick priority higer.
Improved GSM pattern waiting and interrupt processing.
First batch of changes for GPS support
Fix compile warning about missing include
Increase GPS input buffer size.
Add checking if PIN is required.
Remove unnecessary comment.
Add log files and another GPS example script. Before using it, comment line '#define BUILD_GPS' out.
Added new flags that follows modem state
Merge remote-tracking branch 'ruuvi/master' into interrupt
Small modifications.

Removed HW flow control. There is none on GPS uart.
Line handling now skips empty lines.
Modified LUA script to use new flag from gsm driver.

Signed-off-by: Tomi Hautakoski <thauta@iki.fi>
Fixed issue 7.

Gsm Power pin status was not checked before toggling power on or off.
Add buffer sizes in gps and uart.
Merge branch 'master' of github.com:RuuviTracker/ruuvitracker_fw