Support loading a TOML configuration (#229)

docs/example_config.json

@@ -1,54 +0,0 @@
-{
-	"default_profile": "default",
-	"profiles": {
-		"default": {
-			"user_id":  "@user:matrix.org",
-			"url":      "https://matrix.org",
-			"settings": {},
-			"dirs":     {}
-		}
-	},
-	"settings": {
-		"log_level":                  "warn",
-		"message_shortcode_display":  false,
-		"reaction_display":           true,
-		"reaction_shortcode_display": false,
-		"read_receipt_send":          true,
-		"read_receipt_display":       true,
-		"request_timeout":            10000,
-		"typing_notice_send":         true,
-		"typing_notice_display":      true,
-		"users": {
-			"@user:matrix.org": {
-				"name":  "John Doe",
-				"color": "magenta"
-			}
-		},
-		"default_room": "#iamb-users:0x.badd.cafe",
-		"image_preview": {
-			"protocol": {
-				"type": "sixel"
-			},
-			"size": {
-				"width": 66,
-				"height": 10
-			}
-		}
-	},
-	"layout": {
-		"style": "restore"
-	},
-	"macros": {
-		"n|v": {
-			"V": "<C-W>m"
-		},
-		"i": {
-			"jj": "<Esc>"
-		}
-	},
-	"dirs": {
-		"cache":     "/home/user/.cache/iamb/",
-		"logs":      "/home/user/.local/share/iamb/logs/",
-		"downloads": "/home/user/Downloads/"
-	}
-}