Merge pull request #726 from Chilledheart/daemonize_under_osx

Fix daemon mode in multiple programs under OSX
[scripts] remove obsolete setupmac.sh
Merge pull request #731 from Chilledheart/remove_setupmac

[scripts] remove obsolete setupmac.sh
[README] use svg icon for travis-ci
Merge pull request #735 from Chilledheart/use_svg_icon

[README] use svg icon for travis-ci
[build] prevent bad sed usage under osx
Merge pull request #737 from Chilledheart/fix_sed_osx

[build] prevent bad sed usage under osx
[build] Add CMake Build System

  - remove key storage stuff
  - fix daemon build under osx with cmake
  - Set SOVERSION of libseafile to 0
  - remove shared library version
[cleanup] silence multiple compiler warnings

  - silence the warning of uninitialized head_id in putcommit-v2-proc.c
  - silence the warning of implicit declaration of g_open in test-seafile-fmt.c
  - silence the warning of implicit declaration of g_stat in test-cdc.c
  - silence the warning of uninitialized e in merge-recursive.c