add misspell tool fix common spelling mistakes. (#69)

Makefile

@@ -1,6 +1,9 @@
 ALL_SRC := $(shell find . -name '*.go' -type f | sort)
 ALL_PKGS := $(shell go list $(sort $(dir $(ALL_SRC))))
 
+# All source code and documents. Used in spell check.
+ALL_DOCS := $(shell find . -name '*.md' -type f | sort)
+
 GOTEST=go test
 GOTEST_OPT?=-v -race -timeout 30s
 GOTEST_OPT_WITH_COVERAGE = $(GOTEST_OPT) -coverprofile=coverage.txt -covermode=atomic
@@ -17,9 +20,13 @@ $(TOOLS_DIR)/golangci-lint: go.mod go.sum tools.go
 $(TOOLS_DIR)/goimports: go.mod go.sum tools.go
 	go build -o $(TOOLS_DIR)/goimports golang.org/x/tools/cmd/goimports
 
-precommit: $(TOOLS_DIR)/goimports $(TOOLS_DIR)/golangci-lint 
+$(TOOLS_DIR)/misspell: go.mod go.sum tools.go
+	go build -o $(TOOLS_DIR)/misspell github.com/client9/misspell/cmd/misspell
+
+precommit: $(TOOLS_DIR)/goimports $(TOOLS_DIR)/golangci-lint  $(TOOLS_DIR)/misspell 
 	$(TOOLS_DIR)/goimports -d -local github.com/open-telemetry/opentelemetry-go -w .
 	$(TOOLS_DIR)/golangci-lint run # TODO: Fix this on windows.
+	$(TOOLS_DIR)/misspell -w $(ALL_SRC) $(ALL_DOCS)
 
 .PHONY: test-with-coverage
 test-with-coverage:

README.md

@@ -2,7 +2,7 @@
 [![Docs](https://godoc.org/github.com/open-telemetry/opentelemetry-go?status.svg)](http://godoc.org/github.com/open-telemetry/opentelemetry-go)
 [![Go Report Card](https://goreportcard.com/badge/github.com/open-telemetry/opentelemetry-go)](https://goreportcard.com/report/github.com/open-telemetry/opentelemetry-go)
 
-This is a prototype *intended to be modified* into the opentelemetry-go implementation. The `api` directory here should be used as a starting point to introduce a new OpenTelemetry exporter, wherease the existing `exporter/observer` streaming model should be help verify the api 
+This is a prototype *intended to be modified* into the opentelemetry-go implementation. The `api` directory here should be used as a starting point to introduce a new OpenTelemetry exporter, whereas the existing `exporter/observer` streaming model should be help verify the api 
 
 To run the examples, first build the stderr tracer plugin (requires Linux or OS X):
 

go.sum

@@ -6,6 +6,7 @@ github.com/OpenPeeDeeP/depguard v0.0.0-20180806142446-a69c782687b2 h1:HTOmFEEYrW
 github.com/OpenPeeDeeP/depguard v0.0.0-20180806142446-a69c782687b2/go.mod h1:7/4sitnI9YlQgTLLk734QlzXT8DuHVnAyztLplQjk+o=
 github.com/StackExchange/wmi v0.0.0-20180116203802-5d049714c4a6/go.mod h1:3eOhrUMpNV+6aFIbp5/iudMxNCF27Vw2OZgy4xEx0Fg=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
+github.com/client9/misspell v0.3.4 h1:ta993UF76GwbvJcIo3Y68y/M3WxlpEHPWIGDkJYwzJI=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
 github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk=

tools.go

@@ -3,6 +3,7 @@
 package tools
 
 import (
+	_ "github.com/client9/misspell/cmd/misspell"
 	_ "github.com/golangci/golangci-lint/cmd/golangci-lint"
 	_ "golang.org/x/tools/cmd/goimports"
 )