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
```