Refactor to simplify exported files (#95)

Moves content of `baseline-browser-versions.ts` directly to `index.ts` as separation was pointless. This simplifies the exported files, providing a single relevant `index.d.ts` file with no further imports. Also fixes a bug introduced in 2.6.0 where type file was excluded from published modules which broke tooltips.

Author: tonypconway

.gitignore

@@ -5,4 +5,5 @@ baseline-browser-mapping-*.tgz
 .DS_Store
 .idx/
 .vscode/
-.idea/
+.idea/
+.DS_Store