doc: add some database docs.

Author: Christian Hergert

doc/mongoc_database.txt

@@ -14,12 +14,13 @@ SYNOPSIS
 ---------------
 #include <mongoc.h>
 
-mongoc_client_t * client;
-mongoc_database_t * database;
+{
+   mongoc_database_t *database;
+   mongoc_client_t *client;
 
-client = mongoc_client_new(uri_string);
-
-database = mongoc_client_get_database(client, "db_name");
+   client = mongoc_client_new (uri_string);
+   database = mongoc_client_get_database (client, "db_name");
+}
 ---------------
 
 
@@ -57,6 +58,8 @@ linkmongoc:mongoc_database_command[3]
 linkmongoc:mongoc_database_command_simple[3]
 linkmongoc:mongoc_database_drop[3]
 linkmongoc:mongoc_database_has_collection[3]
+linkmongoc:mongoc_database_get_collection[3]
+linkmongoc:mongoc_database_get_name[3]
 linkmongoc:mongoc_database_get_read_prefs[3]
 linkmongoc:mongoc_database_set_read_prefs[3]
 linkmongoc:mongoc_database_get_write_concern[3]

doc/mongoc_database_get_collection.txt

@@ -0,0 +1,33 @@
+mongoc_database_get_collection(3)
+=================================
+
+
+NAME
+----
+
+mongoc_database_get_collection - Fetch a collection within a database
+
+
+SYNOPSIS
+--------
+[source,c]
+-----------------------
+mongoc_collection_t *
+mongoc_database_get_collection (mongoc_database_t *database,
+                                const char        *name);
+-----------------------
+
+
+DESCRIPTION
+-----------
+The _mongoc_database_get_collection()_ function shall return a newly
+allocated mongoc_collection_t for the collection named by _name_.
+
+RETURN VALUE
+------------
+A _mongoc_collection_t_ that should be freed with mongoc_collection_destroy().
+
+
+AUTHORS
+-------
+This page was written by MongoDB, Inc.

doc/mongoc_database_get_name.txt

@@ -0,0 +1,31 @@
+mongoc_database_get_name(3)
+===========================
+
+
+NAME
+----
+
+mongoc_database_get_name - Fetch the name of database
+
+
+SYNOPSIS
+--------
+[source,c]
+-----------------------
+const char *mongoc_database_get_name (mongoc_database_t *database);
+-----------------------
+
+
+DESCRIPTION
+-----------
+The _mongoc_database_get_name()_ function shall return a string containing
+the database name. This value should not be modified or freed.
+
+RETURN VALUE
+------------
+A string which should not be modified or freed.
+
+
+AUTHORS
+-------
+This page was written by MongoDB, Inc.