Patches: Fix compiler warnings, update .gitignore, improve README-hacking

[Max Barraclough]

Thanks Paulo for committing my previous patches.

I've attached:

0001: Patch to fix compiler warnings relating to print format specifiers
0002: Patch for an addition to a .gitignore file
0003: Patch for various improvements to the README-hacking file

With patch 0001 applied, lightning builds with no warnings on my
machine.

(Shipping the patches as attachments, as Outlook is known to mangle
email text even if you're able to get it to work with 'git send-email'.)


   -Max

0001-Fix-compile-warnings-re.-sprintf-format-specifiers.patch
Description: 0001-Fix-compile-warnings-re.-sprintf-format-specifiers.patch

0002-List-new-movzr-check-executable-in-.gitignore.patch
Description: 0002-List-new-movzr-check-executable-in-.gitignore.patch

0003-Improve-README-hacking-especially-re.-dependencies.patch
Description: 0003-Improve-README-hacking-especially-re.-dependencies.patch