Overhaul the examples structure

- main -> examples
- utils -> examples (renamed to "common")
- quantize -> examples
- separate tools for "perplexity" and "embedding"

Hope I didn't break something !

utils.h

@@ -1,64 +0,0 @@
-// Various helper functions and utilities
-
-#pragma once
-
-#include "llama.h"
-
-#include <string>
-#include <vector>
-#include <random>
-#include <thread>
-
-//
-// CLI argument parsing
-//
-
-struct gpt_params {
-    int32_t seed          = -1;   // RNG seed
-    int32_t n_threads     = std::min(4, (int32_t) std::thread::hardware_concurrency());
-    int32_t n_predict     = 128;  // new tokens to predict
-    int32_t repeat_last_n = 64;   // last n tokens to penalize
-    int32_t n_parts       = -1;   // amount of model parts (-1 = determine from model dimensions)
-    int32_t n_ctx         = 512;  // context size
-    int32_t n_batch       = 8;    // batch size for prompt processing
-
-    // sampling parameters
-    int32_t top_k = 40;
-    float   top_p = 0.95f;
-    float   temp  = 0.80f;
-    float   repeat_penalty  = 1.10f;
-
-    std::string model  = "models/lamma-7B/ggml-model.bin"; // model path
-    std::string prompt = "";
-    std::string input_prefix = ""; // string to prefix user inputs with
-
-
-    std::vector<std::string> antiprompt; // string upon seeing which more user input is prompted
-
-    bool memory_f16        = true;  // use f16 instead of f32 for memory kv
-    bool random_prompt     = false; // do not randomize prompt if none provided
-    bool use_color         = false; // use color to distinguish generations and inputs
-    bool interactive       = false; // interactive mode
-
-    bool embedding         = false; // get only sentence embedding
-    bool interactive_start = false; // wait for user input immediately
-
-    bool instruct          = false; // instruction mode (used for Alpaca models)
-    bool ignore_eos        = false; // do not stop generating after eos
-    bool perplexity        = false; // compute perplexity over the prompt
-    bool use_mlock         = false; // use mlock to keep model in memory
-    bool mem_test          = false; // compute maximum memory usage
-    bool verbose_prompt    = false; // print prompt tokens before generation
-};
-
-bool gpt_params_parse(int argc, char ** argv, gpt_params & params);
-
-void gpt_print_usage(int argc, char ** argv, const gpt_params & params);
-
-std::string gpt_random_prompt(std::mt19937 & rng);
-
-//
-// Vocab utils
-//
-
-std::vector<llama_token> llama_tokenize(struct llama_context * ctx, const std::string & text, bool add_bos);