Adding build folders & sorting gitignore

Since these folders are generated during build (and to be ignored).
.gitignore is also sorted for easier maintenance.

Change-Id: I324f89264a523f9bf99c7311eb12e76cb0673b4b
Signed-off-by: Abhishek Lekshmanan <abhishek.lekshmanan@ril.com>

.gitignore

@@ -1,18 +1,18 @@
-*.pyc
-*.egg-info
-.coverage
-.tox
-cover
-.testrepository
-subunit.log
-AUTHORS
-ChangeLog
-dist
-*.egg
-ceilometer/versioninfo
-doc/build
-doc/source/sourcecode
+*.egg*
 *.mo
+*.pyc
+.coverage
+.testrepository
+.tox
+AUTHORS
+build/*
+ceilometer/versioninfo
+ChangeLog
+cover/*
+dist/*
+doc/build/*
+doc/source/sourcecode
 etc/ceilometer/ceilometer.conf*
+subunit.log
 tools/lintstack.head.py
 tools/pylint_exceptions