Renamed encoding to default_encoding

no functionality change. this is just code clean-up.
Supported specific character encoding of source code

Added new config parameter 'encoding_suspects' to put suspects encoding list.
commit diff, normal blob and blame are converted by Encode::Guess with suspects encoding list.
fix bug that dispaly blog image line number
add encoding_suspects test
add changes
add the way to merge other user branch to network/graph page
version up
add search form
allow . as project name
add changes
improve search page
allow . as project name
fix bug that forst . is not allowed
Merge branch 'master' into search
improve search page design
improve search page design
improve search page design
add search feature
fix changes
version up