Documentation fix

Add relevant comments and explanations.
Fix indentation.
Add copyright notes.
diff --git a/library/ecdsa.c b/library/ecdsa.c
index 0f33b83..dba303b 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -289,9 +289,6 @@
 /*
  * Convert a signature to a raw concatenation of {r, s}
  */
-/*int mbedtls_ecdsa_signature_to_raw( const unsigned char *sig,
-                            size_t ssize, uint16_t byte_len,
-                            unsigned char *buf, size_t* slen )*/
 int mbedtls_ecdsa_signature_to_raw( const unsigned char *sig,
                             size_t ssize, uint16_t byte_len,
                             unsigned char *buf, size_t bufsize,
@@ -305,7 +302,7 @@
 
     if( 2 * byte_len > bufsize )
     {
-        return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
+        return (MBEDTLS_ERR_ECP_BAD_INPUT_DATA);
     }
 
     mbedtls_mpi_init( &r );
@@ -326,29 +323,30 @@
     }
 
     if( ( ret = mbedtls_asn1_get_mpi( &p, end, &r ) ) != 0 ||
-            ( ret = mbedtls_asn1_get_mpi( &p, end, &s ) ) != 0 )
+        ( ret = mbedtls_asn1_get_mpi( &p, end, &s ) ) != 0 )
     {
         ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
         goto cleanup;
     }
     p = (unsigned char *) buf;
-    if( ( ret = mbedtls_mpi_write_binary(&r, p, byte_len) ) )
+    if( ( ret = mbedtls_mpi_write_binary( &r, p, byte_len) ) )
     {
         ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
         goto cleanup;
     }
     p += byte_len;
-    if( ( ret = mbedtls_mpi_write_binary(&s, p, byte_len) ) )
+    if( ( ret = mbedtls_mpi_write_binary( &s, p, byte_len) ) )
     {
         ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
         goto cleanup;
     }
     *buflen = 2*byte_len;
-    cleanup:
-        mbedtls_mpi_free( &r );
-        mbedtls_mpi_free( &s );
 
-        return( ret );
+cleanup:
+    mbedtls_mpi_free( &r );
+    mbedtls_mpi_free( &s );
+
+    return( ret );
 }
 
 /*
diff --git a/library/pkcs11_client.c b/library/pkcs11_client.c
index 040b971..700587b 100644
--- a/library/pkcs11_client.c
+++ b/library/pkcs11_client.c
@@ -29,7 +29,6 @@
 
 #include <stdint.h>
 #include <string.h>
-#include <pkcs11.h>
 
 #include "mbedtls/pkcs11_client.h"
 
@@ -144,7 +143,7 @@
     CK_RV rv;
     CK_MECHANISM mechanism = {0, NULL_PTR, 0};
     CK_ULONG ck_sig_len;
-
+    (void)(md_alg);
     /* This function takes size_t arguments but the underlying layer
        takes unsigned long. Either type may be smaller than the other.
        Legitimate values won't overflow either type but we still need
@@ -180,7 +179,8 @@
          * each in the form of a big-endian byte sequence, with r and s
          * having the same length as the base point.
          *
-         * A standard ECDSA signature is encoded in ASN.1:
+         * This library encodes ECDSA signatures in ASN.1 as documented
+         * for mbedtls_ecdsa_write_signature:
          *   SEQUENCE {
          *     r INTEGER,
          *     s INTEGER
@@ -315,7 +315,7 @@
 static const mbedtls_pk_info_t mbedtls_pk_pkcs11_info =
     MBEDTLS_PK_OPAQUE_INFO_1( "pkcs11"
                               , pkcs11_pk_get_bitlen
-                              , pkcs11_pk_can_do //can_do
+                              , pkcs11_pk_can_do
                               , pkcs11_pk_signature_size
                               , pkcs11_verify
                               , pkcs11_sign