Browser compatibility

Currently the library is designed for server-side JS (NodeJS) and uses various NodeJS packages which must be "faked" in browsers (through shims/polyfills) or can't be used at all (e.g., the fs package). As the OSLC client is and will be used in browsers more than on servers, we need to make the library compatible with browsers without the need to have two separate versions of the library to maintain.