Typings: fix compilation error

[yosiat]

index.d.ts:4:1 - error TS1046: Top-level declarations in .d.ts files must start with either a 'declare' or 'export' modifier.

4 namespace GracefulExit {

fixes - #24

[ivolucien]

@yosiat - I haven't used that declare syntax, is that for use as a script? I see a note about "ambient namespaces" in the ts docs but I can't tell if this change would work for all users everywhere...

Thoughts or pointers to help get me up to speed on this?

[benny-medflyt]

Please merge this, it fixes typescript support