Fixes 'no output' issue from #3
Fixes 'no output' issue from #3

## TL;DR
No output file was created because the source files couldn't be found on disk. The source files couldn't be found because the paths in `lib/dependencies` are written relative to the project root, not the `rx` script. This alters the paths to be relative to the `rx` script.

## Output Before
```
○ ~/Sites/rx ‣ ls -alh
total 0
drwxr-xr-x    2 jschulz  staff    68B Jan  6 16:40 .
drwxr-xr-x  262 jschulz  staff   8.7K Jan  6 14:24 ..

○ ~/Sites/rx ‣ rx --lite --methods map,filter,fromevent
Requested operator map
Alias for map found - select
Adding operator select
Requested operator filter
Alias for filter found - where
Adding operator where
Requested operator fromevent
Adding operator fromevent
Adding operator fromeventpattern
Adding operator publish
Adding operator multicast
Adding operator connectableobservable

○ ~/Sites/rx ‣ ls -alh
total 0
drwxr-xr-x    2 jschulz  staff    68B Jan  6 16:40 .
drwxr-xr-x  262 jschulz  staff   8.7K Jan  6 14:24 ..
```

## Output After
```
○ ~/Sites/rx ‣ ls -alh
total 0
drwxr-xr-x    2 jschulz  staff    68B Jan  6 16:40 .
drwxr-xr-x  262 jschulz  staff   8.7K Jan  6 14:24 ..

○ ~/Sites/rx ‣ rx --lite --methods map,filter,fromevent
Requested operator map
Alias for map found - select
Adding operator select
Requested operator filter
Alias for filter found - where
Adding operator where
Requested operator fromevent
Adding operator fromevent
Adding operator fromeventpattern
Adding operator publish
Adding operator multicast
Adding operator connectableobservable

○ ~/Sites/rx ‣ ls -alh
total 0
drwxr-xr-x    3 jschulz  staff   102B Jan  6 16:40 .
drwxr-xr-x  262 jschulz  staff   8.7K Jan  6 14:24 ..
drwxr-xr-x    4 jschulz  staff   136B Jan  6 16:40 build

○ ~/Sites/rx ‣ ls -alh build/
total 232
drwxr-xr-x  4 jschulz  staff   136B Jan  6 16:40 .
drwxr-xr-x  3 jschulz  staff   102B Jan  6 16:40 ..
-rw-r--r--  1 jschulz  staff    86K Jan  6 16:40 rx.custom.js
-rw-r--r--  1 jschulz  staff    27K Jan  6 16:40 rx.custom.min.js
```
Reactive-Extensions/RxJS-CLI