lpar: Check for illegal characters in $repo

Only '-', '.', '/', 0-9, A-Z, underscore and a-z are allowed.

93ba19f6-bcff-11e3-ac3e-001f3b596ec9
0bc07050-be43-11e3-a4d1-001f3b596ec9
lpar: Check that all command line args point to a valid commit

e02a4844-bd07-11e3-9ccf-001f3b596ec9
build-git: lpar_git(): Remove repo name from lpar command

lpar(1) reads the repo name from lpar.name now.

c0ee7030-bd08-11e3-b25d-001f3b596ec9
1411e4ee-bd0a-11e3-92e4-001f3b596ec9
all-lpar: Execute "lpar" instead of "lpar -a" in all subdirs

Should probably add a -r/--recursive option to lpar someday instead. But
it'll do for now.

c6287798-bd13-11e3-bcb4-001f3b596ec9
Merge branch 'lpar.use-lpar-name'

Read repository name from the git config variable repo.name instead of
specifying it on the command line.

* lpar.use-lpar-name:
  all-lpar: Execute "lpar" instead of "lpar -a" in all subdirs
  build-git: lpar_git(): Remove repo name from lpar command
  lpar: Check that all command line args point to a valid commit
  lpar: Check for illegal characters in $repo
  lpar: Use lpar.name from git config instead of $ARGV[0]

924f7ce2-be43-11e3-a79a-001f3b596ec9