After a failed build, re-running `gulp` results in an EEXIST error

[txinfo]

On windows:

[15:53:55] Starting 'clean:dist'...
[15:53:55] Starting 'clean:tmp'...
[15:53:55] Starting 'clean:build'...
[15:53:55] Starting 'compile'...
[15:53:55] Starting 'watch'...
[15:53:56] Finished 'watch' after 422 ms
[15:53:56] Finished 'compile' after 426 ms
[15:53:56] Finished 'clean:dist' after 440 ms
[15:53:56] Starting 'copy:source'...
[15:53:56] Finished 'clean:build' after 445 ms
[15:53:56] Finished 'clean:tmp' after 551 ms
[15:53:56] Starting 'clean'...
[15:53:56] Finished 'clean' after 2.13 μs
[15:53:56] Starting 'build'...
[15:53:56] Finished 'build' after 4.27 μs
[15:53:56] Starting 'build:watch'...
[15:53:56] Finished 'build:watch' after 3.41 μs
[15:53:56] Starting 'default'...
[15:53:56] Finished 'default' after 5.12 μs
[15:53:56] 'copy:source' errored after 122 ms
[15:53:56] Error: EEXIST: file already exists, mkdir '<path>\.tmp'
at Error (native)
ERROR: EEXIST: file already exists, mkdir '<path>\.tmp'

Re-running gulp fixes the error.

[izifortune]

#261 Should fix this issue