Added new modules to library

- gc_i2c_slave     -- generic I2C slave to be used with a processor or tied to a
                      Wishbone interface
- gc_glitch_filter -- glitch filter with selectable number of taps
- wb_i2c_bridge    -- I2C bridge implementing the protocol defined with ELMA
                      for monitoring VME crates
- wb_xil_multiboot -- module that accesses the Spartan-6 configuration logic
                      for reconfiguring the FPGA using MultiBoot

Doc files for each of these modules can be found in the doc/ folder.

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Added gc_fsm_watchdog component

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Fixed the FSM watchdog max value bug

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Updates in wb_xil_multiboot module

- an FSM watchdog component was added to the multiboot_fsm; the timeout of
the wathcdog is reflected in the component's status register
- multiboot_regs was wbgen-ized
- updated wb_xil_multiboot top-level to reflect new changes

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Made I2C slave and bridge work properly

- I2C slave component now samples SDA line one rising SCL and changes
states and shifts out bits on its falling edge
- I2C slave component has clearer status outputs
- bridge component changed to reflect changes in I2C slave interface
- bridge component also returns to IDLE state on I2C stop condition, as
reflected by the I2C slave

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Small clean-up in gc_i2c_slave module and the instantiating wb_i2c_bridge module

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
Updated some documentation files

Signed-off-by: Theodor Stana <t.stana@cern.ch>
Signed-off-by: Tomasz Włostowski <tomasz.wlostowski@cern.ch>
gencores_pkg: added missing function declarations that were upsetting ISE
Merge remote-tracking branch 'ohwr/master'