jsonrpc.js doesn't create global variable jsonrpc in browser

Unable to use jsonrpc.js umd file in browsers:

Uncaught ReferenceError: jsonrpc is not defined

Also impossible to use with rollup.js

[!] Error: 'parse' is not exported by ./node_modules/jsonrpc-lite/jsonrpc.js

[antongolub]

@makoven , could you test the patch proposal? Just replace node_modules/jsonrpc-lite with this inners and check this out.