Generate Rusty wrapper by procedural macro, merge lapack crate

[termoshtt]

Depends on #11

• Replace Python script to generate rusty wrapper at lapack/bin by proc-macro crate lapack-derive
• Introduce cargo-workspace for adding lapack-derive crate
• Integrate lapack crate features into lapack-sys crate

How proc-macro works

This PR adds #[lapack] attribute for every extern "C" block generated by #11 :

#[lapack]                
extern "C" {               
    pub fn dgetrs_(                    
        trans: *const c_char,
        n: *const c_int,                
        nrhs: *const c_int, 
        A: *const f64,       
        lda: *const c_int, 
        ipiv: *const c_int,
        B: *mut f64,     
        ldb: *const c_int,            
        info: *mut c_int, 
    );                                
}

lapack_derive::lapack expands it into following:

extern "C" {               
    pub fn dgetrs_(                    
        trans: *const c_char,
        n: *const c_int,                
        nrhs: *const c_int, 
        A: *const f64,       
        lda: *const c_int, 
        ipiv: *const c_int,
        B: *mut f64,     
        ldb: *const c_int,            
        info: *mut c_int, 
    );                                
}

pub unsafe fn dgetrs(        
    trans: c_char,                                         
    n: c_int,        
    nrhs: c_int,                
    A: &[f64],        
    lda: c_int,        
    ipiv: &[c_int],        
    B: &mut [f64],        
    ldb: c_int,        
    info: &mut c_int        
) {              
    dgetrs_(        
        &trans,        
        &n,               
        &nrhs,          
        A.as_ptr(),        
        &lda,                    
        ipiv.as_ptr(),        
        B.as_mut_ptr(),        
        &ldb,             
        info                  
    )                          
}     

In lapack crate, it is done by the Python script and generated Rust code is committed. This PR proposes merging lapack crate into lapack-sys crate. You can confirm the generated result by cargo doc --no-deps.

Conversion rule

• *const T is converted into &[T] by default
  • Whitelisted names e.g. uplo, trans, and so on, are regarded as T, and pass by &value to FFI.
  • The list is implemented in lapack_derive::is_value function
• *mut T is converted into &mut [T] by default
  • Whitelisted names e.g. info, rcond, are regarded as &mut T
  • The list is implemented in lapack_derive::is_mut_ref function