Change check_link_is_dir() => get_symlink_type()

To avoid cryptic == 2 check.
Use overwrite flag in ops.c:op_mv()/op_cp()
Introduce ConflictAction in ops.c
Fix type of crs variable in iop_cp()
Implement file appending in i/o
Add copy and move ops that append files
Define _FILE_OFFSET_BITS as 64 for Windows

Just in case.
Document return value of utils/fs:get_file_size()
Fix ops.c compilation on Windows

And also passing of conflict_action parameter through.
Don't use ftello()

It's not very portable and its result can be replaced with file size.
Check for cancellation on copying on Windows
Fallback to internal copy alg for Win partial copy
Added "a[p]pend the end" conflict resolution opt

Appends the rest of file, e.g. if previous operation was terminated.

Available only if 'syscalls' option is set.

Thanks to Sergei Shilovsky.
Merge branch 'add-file-appending'

Add "a[p]pend the end" conflict resolution option (appends the rest of
file, e.g. if previous operation was terminated).  Available only if
'syscalls' option is set.

Thanks to Sergei Shilovsky.

Bug report #41 of SourceForge.