[TASK] Revise Altera Qsys subsystems

- Add flash bridges to subsystems.
- Add EPCS flash in toplevel Qsys connected to flash bridge.
- Solve warnings by exporting openMAC timer outport.
- Increase slow bridge address width to 19.

Change-Id: I25470acf5f1f5e9cc23ac90bd115f54bec84bbf6
[TASK] Revise EPCS Flash programming

- Add program-epcs.sh script that can program an EPCS flash without
  connecting to Nios II instance (no need to erase flash before).
- Add EPCS support to driver application scripts.
- Add chain and converter setting files to TERASIC DE2-115 board.

Change-Id: Ia03a2dcd211c150cdb429b8e3dca42377cfdacec
[FEATURE] Add Altera Nios II EPCS flash bootloader

Add EPCS flash bootloader for Cyclone IV designs, which is derived from
the default Nios II bootloader sources provided in Quartus V13.0sp1.
- Adapt Makefile to directory structure
- Remove Cyclone I/II sources
- Remove CFI flash source
- Remove EPCQ flash source
- Remove trailing whitspaces

Change-Id: Ib0eb29878d3dfc5b701ed2f429e3cfcad438ef05
[FEATURE] Revise Nios II EPCS bootloader for remote update

Add IMAGE_BOOT_BASE parameter which enables the bootloader to boot from
addresses other than zero within EPCS flash. This feature is needed to
boot from update images.

Change-Id: I9f508485b61e4019d1816d26a05a5e6528e3615a