Organize .gitignore and also ignore build dir stuff

Sort the stuff alphabetically, add some comments, ignore stuff that can
appear in build directories, so we don't have to guess the build
directory's name.

.gitignore

@@ -1,40 +1,74 @@
+# The following three lines exclude all files (not directories) which don't
+# have a period in them. This should exclude executables on non-Windows
+# platforms.
 *
 !**/
 !*.*
 
+# Ignore data-folders outside the root, these are copied around to build
+# directories.
+data/
+!/data/
+
+bundle/
+!/other/bundle/
+
+.ninja_deps
+.ninja_log
+CMakeCache.txt
+CMakeFiles
+CMakeSettings*
+CPackConfig.cmake
+CPackSourceConfig.cmake
+CTestTestfile.cmake
+_CPack_Packages/
+build.ninja
+cmake_install.cmake
+gmock.pc
+gmock_main.pc
+googletest-build/
+googletest-download/
+googletest-src/
+gtest.pc
+gtest_main.pc
+pack_*/
+rules.ninja
+testrunner\[1\]_include.cmake
+
 src/game/generated
 
 .cproject
 .project
-*.exe
+.settings
+cscope.files
+cscope.out
+
+# bam ignores
+/config.lua
+/objs
+
+*.cmd
 *.dll
+*.dmg
 *.dtb
-*.log
-*.res
-*.patch
-*.prefs
+*.exe
+*.filters
 *.lnk
+*.log
+*.opensdf
+*.patch
 *.pdb
+*.prefs
+*.pyc
+*.res
 *.sdf
 *.sln
 *.suo
 *.swp
-*.vs
-*.vcxproj
-*.filters
+*.tar.gz
+*.tar.xz
+*.teehistorian
 *.user
-*.cmd
-.settings
-*.opensdf
-*.pyc
-cscope.out
-cscope.files
-
-CMakeCache.txt
-CMakeSettings*
-CMakeFiles
-CPackConfig.cmake
-CPackSourceConfig.cmake
-_CPack_Packages/
-cmake_install.cmake
-/build/
+*.vcxproj
+*.vs
+*.zip