Add search functionality

Search will now find transactions or blocks if given the hash. From @ericecook
Three options I suppose

1. Use POST. This means that going backward then forward usually prompts for form resubmission. We don't really want that here.
2. Use GET. No prompt when going through history. It also will cause google and the like to not index/cache these pages I believe.
3. Use canoncial URLs. This is probably not what we want here since google will index and cache the page.

Just switch method to GET and toss the JS I think.