update git ignore to ignore only certain files/dirs in shogun/doc
update git ignore to ignore only certain files/dirs in shogun/doc

sorig/shogun,shogun-toolbox/shogun,Saurabh7/shogun,sorig/shogun,shogun-toolbox/shogun,sorig/shogun,Saurabh7/shogun,karlnapf/shogun,lisitsyn/shogun,sorig/shogun,geektoni/shogun,besser82/shogun,karlnapf/shogun,karlnapf/shogun,karlnapf/shogun,shogun-toolbox/shogun,Saurabh7/shogun,lambday/shogun,besser82/shogun,lambday/shogun,geektoni/shogun,besser82/shogun,shogun-toolbox/shogun,shogun-toolbox/shogun,lisitsyn/shogun,karlnapf/shogun,lambday/shogun,Saurabh7/shogun,lambday/shogun,Saurabh7/shogun,Saurabh7/shogun,geektoni/shogun,lambday/shogun,Saurabh7/shogun,besser82/shogun,lisitsyn/shogun,Saurabh7/shogun,geektoni/shogun,lisitsyn/shogun,besser82/shogun,geektoni/shogun,sorig/shogun,lisitsyn/shogun,Saurabh7/shogun,shogun-toolbox/shogun,besser82/shogun,geektoni/shogun,sorig/shogun,lisitsyn/shogun,lambday/shogun,karlnapf/shogun