The maximum read/write size for the Memory class should be increased

**Describe the bug**
Some users wish to read/write strings longer than 4096 bytes.

Doing so results in errors such as:
```
[18/08/25 19:08:32:26] Read string var 'full_txt_144x16' failed: Couldn't read memory for object of type byte[] @604591740; it wouldn't fit in the read buffer (tried reading 4638 bytes into 4096)!
```
