shell: Shell subsystem reimplementation

New shell support features like:
- multi-instance
- command tree
- static and dynamic commands
- multiline
- help print function
- smart tab (autocompletion)
- meta-keys
- history, wildcards etc.
- generic transport (initially, uart present)

Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>

include/shell/shell_fprintf.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2018 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef SHELL_FPRINTF_H__
+#define SHELL_FPRINTF_H__
+
+#include <zephyr.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void (*shell_fprintf_fwrite)(const void *user_ctx,
+				      const char *data,
+				      size_t length);
+
+struct shell_fprintf_control_block {
+	size_t buffer_cnt;
+	bool autoflush;
+};
+/**
+ * @brief fprintf context
+ */
+struct shell_fprintf {
+	u8_t *buffer;
+	size_t buffer_size;
+	shell_fprintf_fwrite fwrite;
+	const void *user_ctx;
+	struct shell_fprintf_control_block *ctrl_blk;
+};
+
+
+/**
+ * @brief Macro for defining shell_fprintf instance.
+ *
+ * @param _name		Instance name.
+ * @param _user_ctx	Pointer to user data.
+ * @param _buf		Pointer to output buffer
+ * @param _size		Size of output buffer.
+ * @param _autoflush	Indicator if buffer shall be automatically flush.
+ * @param _fwrite	Pointer to function sending data stream.
+ */
+#define SHELL_FPRINTF_DEFINE(_name, _user_ctx, _buf, _size,	\
+			    _autoflush, _fwrite)		\
+	static struct shell_fprintf_control_block		\
+				_name##_shell_fprintf_ctx = {	\
+		.autoflush = _autoflush,			\
+		.buffer_cnt = 0					\
+	};							\
+	static const struct shell_fprintf _name = {		\
+		.buffer = _buf,					\
+		.buffer_size = _size,				\
+		.fwrite = _fwrite,				\
+		.user_ctx = _user_ctx,				\
+		.ctrl_blk = &_name##_shell_fprintf_ctx		\
+	}
+
+/**
+ * @brief fprintf like function which send formated data stream to output.
+ *
+ * @param sh_fprintf	fprintf instance.
+ * @param fmt		Format string.
+ * @param args		List of parameters to print.
+ */
+void shell_fprintf_fmt(const struct shell_fprintf *sh_fprintf,
+		       char const *fmt, va_list args);
+
+/**
+ * @brief function flushing data stored in io_buffer.
+ *
+ * @param sh_fprintf	fprintf instance
+ */
+void shell_fprintf_buffer_flush(const struct shell_fprintf *sh_fprintf);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SHELL_FPRINTF_H__ */