fix examples installation, thanks to qrilka.

see
https://github.com/haskell/haskell-mode/commit/78e973fbf42637d34503f3a18b61d0a24c3e07ca
dev-haskell/tcache: bump up to 0.10.0.8

Signed-off-by: Alexander Vershilov <alexander.vershilov@gmail.com>
add the keywords to haddock-2.13.2, drop the deepseq dep (its a ghc core lib so deepseq is always there anyway)
haskell-platform-2013.2.0.0 wants haddock-2.13.2
Fix haddock 2.13.2 build with doc USE flag