[lmi] [PATCH] Install wxPdfDocument using Git

[Vadim Zeitlin]

 Hello,

 I've created a PR replacing the existing install_wxpdfdoc.make, using wget
to download the library snapshot from Github, with install_wxpdfdoc.sh
which uses Git to get the sources directly. The new script is very similar
to the existing install_wx.sh and, in fact, I wonder if we should reuse the
common parts of the two scripts via some common install_functions.sh that
could be sourced by both scripts. But for now I've kept things simple and
didn't do it, please let me know if I should.

 The changes themselves are at https://github.com/vadz/lmi/pull/91 and I've
tested them by running the script with and without wxpdfdoc_commit_sha
argument, it seems to work correctly. In particular, I could test my own
proposed changes to configure.ac that were supposed to fix the problem with
autoreconf and found that they broke the build instead, so they definitely
shouldn't be applied (and I still have no idea why does that problem
happen, unfortunately).

 As usual, please let me know if you have any questions or comments,
VZ