bugfix: examples that load binaries using fopen must use "rb" mode, "r" is insufficient on some platforms.

[adv-sw]

Tried loading another file into hello.c & it failed because text read mode open instead of binary.

Sample code hello.c currently reads :

FILE* file = fopen("hello.wasm", "r");

Should read :

FILE* file = fopen("hello.wasm", "rb");