release next major version v2.8.1

Bug Fixes:

Fix typo in man page (s/BUILD_MODULE_NAME/BUILT_MODULE_NAME)
Merge pull request #77 from sil2100/dont-remove-built-tree
Revert "FIX dkms built issues for rhel kernel update ,change prerm script to fix."
Update README.md
Merge pull request #71 from LocutusOfBorg/patch-1
Update Makefile to install bash_completion file in new usr/share location
Merge pull request #65 from c0d3z3r0/for-upstream/fix_pacman_confusion
Merge pull request #66 from DIGImend/compare_same_module_version_types
Preserve module version type positions
Do not touch original modules in /kernel
Merge pull request #63 from calancha/master
Merge pull request #61 from c0d3z3r0/for-upstream/fix_rmdir
Merge pull request #60 from tonyhutter/fix-module-version-check
Fix syntactic error when the system shell is zsh
Revert "Fix to run under BusyBox shell"
Fix version check when installing modules