Tweak gcc build instructions

Merge pull request #28 from Wren6991/fix-21

Coding style change for Verilator compatibility (fixes #21)

Merge pull request #23 from Wren6991/fix-dm-abstractauto-regno

Fix abstract command using wrong register when initiated by abstractauto

Add note on branches to Contributing.md

Fix initiation of SBA reads not being masked by previous SBA error or…

… busy error.

Update embench config and readme