fileinfo: implement os_fileinfo_size

this replaces os_get_file_size and file_info.stat.st_size
fileinfo: implement os_fileinfo_hardlinks
fileinfo: implement os_fileinfo_blocksize
fileinfo: rename os_get_file_info{,_link,_fd}
fileinfo: rename os_file_info_id_equal
fileinfo: rename os_file_info_get_id
fileinfo: rename os_file_info_get_inode
fileid: rename os_get_file_id
fileid: rename os_file_id_equal
fileid: rename os_file_id_equal_file_info
fileinfo: change returntype of os_fileinfo_size

off_t -> uint64_t
vim-patch: 7.4.330

Problem:    Using a regexp pattern to highlight a specific position can
be slow.
Solution:   Add matchaddpos() to highlight specific positions
efficiently.
(Alexey Radkov.)

https://code.google.com/p/vim/source/detail?r=f9fa2e506b9f07549cd91074835c5c553db7b3a7
vim-patch: 7.4.334

Problem:    Unitialized variables, causing some problems.
Solution:   Initialize the variables. (Dominique Pelle)

https://code.google.com/p/vim/source/detail?r=03d260a8ea0c0c67f424c387dbe2af5754e5e589
vim-patch: 7.4.362

Problem:    When matchaddpos() uses a length smaller than the number of
bytes in the (last) character the highlight continues until the end of
            the line.
Solution:   Change condition from equal to larger-or-equal.

https://code.google.com/p/vim/source/detail?r=7fa2bed947fde3514a700c96861a537d816d6fd4
vim-patch: 7.4.343

Problem:    matchdelete() does not always update the right lines.
Solution:   Fix off-by-one error.  (Ozaki Kiichi)

https://code.google.com/p/vim/source/detail?r=539ce56d8f35fe2deb5c4f57335e1adf97ae4e74
vim-patch: 7.4.344

Problem:    Unnecessary initializations and other things related to
	    matchaddpos().
Solution:   Code cleanup. (Alexey Radkov)

https://code.google.com/p/vim/source/detail?r=ce284c205558d103326a4c3f22f181774690b3eb
Merge pull request #1054 from stefan991/fileinfo-getter

FileInfo getters for `filesize`, `hardlinks` and `blocksize`
Merge pull request #1107 from fmoralesc/matchaddpos

Add matchaddpos()-related vim patches. [vim-patch: 7.4.330, 7.4.334, 7.4.343, 7.4.344, 7.4.362]