Update CMakeLists.txt

This commit includes checking whether ../data directory (from build directory) and ../../stk-assets directory (from build directory) exists or not. If they don't exist, then it gives error message for the corresponding directory. I have included the code for this on line 320.
Update CMakeLists.txt
added achievement banana lover
added an achievement banana lover
merged code with upstream master
Use some diffent value/equation for tonemap
Revert "Use some realist order of magnitude of light"

This reverts commit 2aa6676050c3142b634f2e6063fdfa76435befe5.
Merge branch 'master' of https://github.com/whichrakesh/stk-code into whichrakesh-master
Fix counting of bananas only for current player. Fixed conflicts.
Conflicts:
	src/achievements/achievement_info.hpp
Revert "Some color are negative, clamp them in loglum"

This reverts commit 43df357cfbdba74b2e1d6e7b5b79fabc2377a6b4.
SSAO: Clamp to 0.
Remove color_in, it's been superseeded

Keep the shader because it will be partly used for dof.
Removed swap file added accidentally.
Tweak exposure/whiepoint/saturation
Reorder post processes effects.
Fix normalmap roughness
Revert "Revert "Enable tonemap.""

This reverts commit e57339841b7f6a58329e3e5997776f492bfccfd3.
Revert "Revert "Use a less intrusive delta value""

This reverts commit 230076ffcbd05ecf8a05c165a95fec7823687c4a.
Revert "Revert "Fix a typo in tonemap.frag""

This reverts commit 812b2afcd83eeb8def9cbe6ba665584c1cb0e7d5.
Merge branch 'tonemap'

Conflicts:
	data/shaders/tonemap.frag
Properly add Depth of Field