…ustom.yaml in user data dir, with librime 1.7.3

2. fix: LF in candidate makes crash.  yet LF is not support as part of candidate. pls use CR instead.
3. fix: tip icon position not correct when display scale not 100%
4. enhancement: longer candidate support, <滕王阁序> tested.
5. feat: style/layout/max_width for horizontal layout, default zero to disable.
6. feat: cn tip icon for schema,  in user data dir or share data dir with setting patch:    schema/icon: xxx.ico