Merge pull request #577 from chrox/master

fix page to screen rect transform for highlighting
remove newline when exporting highlight to My Clipping
disable exporting hightlights to My Clippings
fix inconsistant notes between myclipping and history
fix ffi.cast to uint32_t in ARM
I don't know if it's a bug in luajit but on an x86_64 CPU:
```lua
> = ffi.cast("uint32_t", 0xFFFFFFFFE) + 0
4294967294LL
```
while on an ARM CPU:
```lua
> = ffi.cast("uint32_t", 0xFFFFFFFFE) + 0
4294967295LL
```
busted test for frontend
export highlighted rect in scanned page to Evernote