WebAssembly support!

Quite a lot going on in this PR:
 * Updates to support recent emscripten, switching to WASM which is now the default
 * Use emscripten's MODULARIZE option rather than wrapping it ourself, since doing
   so in pre-post js doesn't work anymore.
 * Most changes are moving the emscripten runtime functions to top-level
   calls rather than in the Module object.
 * Get rid of duplicated NULL_BYTE_PADDING_LENGTH
 * Fix ciphertext_length used without being declared
 * Fix things that caused the closure compiler to error, eg. using
   OLM_OPTIONS without a declaration.
 * Wait until module is inited to do OLM_ERROR = olm_error()

The main BREAKING CHANGE here is that the module now needs to initialise
asyncronously (because it has to load the wasm file). require()ing olm
now gives a function which needs to be called to create an instance.
The resulting object has a promise-like then() method that can be used
to detect when the module is ready. (We could use MODULARIZE_INSTANCE
to return the module directly as before, rather than the function,
but then we don't get the .then() method).

1 files changed, 5 insertions, 2 deletions

diff --git a/javascript/test/megolm.spec.js b/javascript/test/megolm.spec.js
index 8f9d24a..9d5eb72 100644
--- a/javascript/test/megolm.spec.js
+++ b/javascript/test/megolm.spec.js
@@ -16,12 +16,15 @@ limitations under the License.
 
 "use strict";
 
-var Olm = require('../olm');
+var Olm = require('../olm')();
 
 describe("megolm", function() {
     var aliceSession, bobSession;
 
-    beforeEach(function() {
+    beforeEach(function(done) {
+        Olm.then(function() {
+            done();
+        });
         aliceSession = new Olm.OutboundGroupSession();
         bobSession = new Olm.InboundGroupSession();
     });