Another strategy for incremental builds

While the `gulp-changed` and `gulp-cached` plugins work great with 1:1 src:dest file mapping, they should not be used for n:1 src:dest mapping.  With plugins like `gulp-concat`, `css-sprite`, etc. that generate a single output file given many input files, you want to compare the modification time of the output file to the modification file of each input file (and use all if any are newer).

The `gulp-newer` plugin works with both 1:1 and n:1 src:dest mapping by comparing `mtime`.
Merge pull request #351 from tschaub/patch-1

Another strategy for incremental builds
closes #366
Rename concat to merge.

https://github.com/dominictarr/event-stream#merge-stream1streamn
Merge pull request #367 from steida/master

Rename concat to merge.
Update using-coffee-script-for-gulpfile.md
Merge pull request #373 from meleyal/patch-1

Update "Using coffee-script for gulpfile" recipe with link to cult
dont exit the process or stop watching on error
fix(watch): preserve options parameter if no callback

Only if the second parameter is a function will the options object be overwritten to null.

This logic is consistent with glob-watcher, such that options can be passed in cases where
a callback function is not supplied.
Merge pull request #379 from stu-salsbury/gaze-opts-lost

fix(watch): preserve options parameter if no callback
fix(watch): handle array of tasks when no options

If second parameter is array, assume no options provided.
Merge pull request #380 from stu-salsbury/watch-fn-array-when-no-opts

fix(watch): handle array of tasks when no options
add gulp-remember to incremental build readme, add related recipe
add docs about chalks color closes #385
Update guidelines.md

Added missing 'new' because of "Call PluginError using new"
Merge pull request #389 from akoenig/patch-1

Update guidelines.md
Make an explicit pointer to the base option

And the other glob-stream options.
fixed david-dm links typo.
Merge pull request #393 from ngryman/master

fixed david-dm links typo.
Merge pull request #392 from xixixao/patch-1

Make an explicit pointer to the base option