Fixed shell portablility
bug #5 Fixed shell portablility (alquerci)

This PR was submitted for the 0.2-dev branch but it was merged into the 0.1 branch instead (closes #5).

Discussion
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| Q               | A
| --------------- | ---
| Bug fix?        | yes
| New feature?    | no
| BC breaks?      | no
| Deprecations?   | no
| Tests pass?     | yes
| Related tickets |
| License         | GNU GPLv3

Commits
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f54d8b8 Fixed shell portablility
Merge branch '0.1'

* 0.1:
  Fixed shell portablility

Conflicts:
	src/git-version-gen.sh
Added `--fallback` option